U.S. patent application number 11/522291 was filed with the patent office on 2007-06-21 for telecommunication system, method and subscriber unit for use therein.
This patent application is currently assigned to SBC Properties, L.P.. Invention is credited to Robert Wesley JR. Bossemeyer, Scott Christopher Goering, Michael George Gorman, Denise Violetta Kagan, Jeffrey Neumann, David Orwick, Michael Steven Pickard, Bruce Edward Stuckman, Michael Tisiker.
Application Number | 20070140228 11/522291 |
Document ID | / |
Family ID | 22382536 |
Filed Date | 2007-06-21 |
United States Patent
Application |
20070140228 |
Kind Code |
A1 |
Gorman; Michael George ; et
al. |
June 21, 2007 |
Telecommunication system, method and subscriber unit for use
therein
Abstract
A telecommunication system includes a digital switch, a local
loop coupling the digital switch to a subscriber location, wherein
a segment of the local loop includes copper twisted pair and
wherein an asymmetrical digital subscriber line is carried by the
local loop, the asymmetrical digital subscriber line including a
plurality of data packets capable of carrying a plurality of
derived digital telephone lines. The telecommunication system
further includes a subscriber unit coupled to the asymmetrical
digital subscriber line. The subscriber unit monitors the content
of at least one of the plurality of data packets, receives an
off-hook signal in response to an action of a user, and initiates a
first derived digital telephone line of the plurality of derived
digital telephone lines in response to the off-hook signal.
Inventors: |
Gorman; Michael George;
(Schaumburg, IL) ; Bossemeyer; Robert Wesley JR.;
(St. Charles, IL) ; Pickard; Michael Steven;
(Highland Park, IL) ; Kagan; Denise Violetta;
(Riverwoods, IL) ; Goering; Scott Christopher;
(Naperville, IL) ; Stuckman; Bruce Edward;
(Algonquin, IL) ; Tisiker; Michael; (Westland,
MI) ; Neumann; Jeffrey; (Hoffman Estates, IL)
; Orwick; David; (Crystal Lake, IL) |
Correspondence
Address: |
BRINKS HOFER GILSON & LIONE
P.O. BOX 10395
CHICAGO
IL
60610
US
|
Assignee: |
SBC Properties, L.P.
|
Family ID: |
22382536 |
Appl. No.: |
11/522291 |
Filed: |
September 14, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
10036861 |
Dec 21, 2001 |
7126958 |
|
|
11522291 |
Sep 14, 2006 |
|
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09119094 |
Jul 20, 1998 |
6370149 |
|
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10036861 |
Dec 21, 2001 |
|
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Current U.S.
Class: |
370/356 |
Current CPC
Class: |
H04M 1/56 20130101; H04M
1/57 20130101; H04M 7/0069 20130101; H04M 1/2535 20130101; H04M
1/715 20210101 |
Class at
Publication: |
370/356 |
International
Class: |
H04L 12/66 20060101
H04L012/66 |
Claims
1-64. (canceled)
65. A subscriber unit comprising: a broadband interface configured
to communicate data streams of data packets corresponding to a
communication along a digital communication line; a coding/decoding
unit configured to communicate data streams and data packets; a
converter in communication with the coding/decoding unit, the
converter configured to translate between one or more of the
communicated data streams or an analog signal; and a user interface
unit in communication with a smart card, the user interface unit
configured to communicate the analog signal and to generate an
acoustic signal based on the analog signal.
66. The subscriber unit of claim 65, wherein the user interface
unit further comprises a smart card interface unit sized to accept
the smart card.
67. The subscriber unit of claim 65, wherein the smart card
includes a memory programmed to store a plurality of data
associated with a user.
68. The subscriber unit of claim 65, wherein the user interface
unit further comprises a keypad in communication with a dual tone
multi-frequency generator.
69. The subscriber unit of claim 65, wherein the user interface
unit further comprises a telephone handset.
70. The subscriber unit of claim 69, wherein the telephone handset
is a digital telephone in communication with the digital
communication line, the digital telephone configured to communicate
a data stream representative of a voice call over the digital
communication line.
71. The subscriber unit of claim 65, wherein the user interface
unit further comprises a processor in communication with a
memory.
72. The subscriber unit of claim 71, wherein the memory comprises a
program logic executable by the processor, the program logic
comprising instructions for causing the processor to manipulate
caller identification information related to an incoming call.
73. The subscriber unit of claim 71, wherein the memory comprises a
program logic executable by the processor, the program logic
comprising instructions for causing the processor to provide caller
identification information related to an incoming call to a display
in communication with the processor.
74. A subscriber unit comprising: a broadband interface configured
to communicate at least one data stream comprising a plurality of
data packets, wherein the at least one data stream corresponds to
at least one communication carried along a broadband communication
line; a communication device configured to: manipulate the at least
one of the data stream or the plurality of data packets that
comprise the at least one data stream; and translate between the at
least one data stream and an analog signal; a user interface unit
configured to communicate the analog signal and to generate an
acoustic signal based on the analog signal; and a smart card
interface in communication with the user interface unit, the smart
card interface configured to communicate user information received
from a smart card.
75. The subscriber unit of claim 74, wherein the user interface
unit further comprises a telephone keypad in communication with a
dual tone multi-frequency generator.
76. The subscriber unit of claim 74, wherein the user interface
unit further comprises a telephone handset.
77. The subscriber unit of claim 76, wherein the telephone handset
is a digital telephone in communication with the broadband
communication line, the digital telephone configured to communicate
a voice data stream representative of a voice call over the
broadband communication line.
78. The subscriber unit of claim 74, wherein the user interface
unit further comprises a processor in communication with a
memory.
79. The subscriber unit of claim 78, wherein the memory comprises a
program logic executable by the processor, the program logic
comprising instructions for causing the processor to manipulate
caller identification information related to an incoming call.
80. The subscriber unit of claim 78, wherein the memory comprises a
program logic executable by the processor, the program logic
comprising instructions for causing the processor to provide caller
identification information related to an incoming call to a display
in communication with the processor.
81. A method of utilizing a subscriber unit to conduct voice and
data communications, the method comprising: transmitting at least
one data stream comprising a plurality of data packets
corresponding to a communication along a digital communication
line, wherein the plurality of data packets and the at least one
data stream are manipulated therebetween, and wherein the at least
one data stream is converted to provide an analog signal; and
communicating the at least one data stream and the plurality of
data packets to a network address received from a smart card in
communication with the digital communication line.
82. The method of claim 81 further comprising: establishing a
plurality of data channels, each of the data channels configured to
communicate one or more of the at least one data stream and the
plurality of data packets.
83. The method of claim 81 further comprising: providing caller
identification data suitable for identifying an incoming caller
associated with the at least one data stream and the plurality of
data packets.
84. The method of claim 83, wherein identifying the incoming caller
includes identifying a facsimile transmission associated with the
at least one data stream and the plurality of data packets.
85. A subscriber unit comprising: a digital telephone configured to
communicate with a broadband communication line, the digital
telephone configured to communicate a data stream representative of
a voice call over the broadband communication line; a keypad in
communication with a dual tone multi-frequency generator and the
digital telephone; a communications device configured to
communicate an analog signal received via the digital telephone and
to generate an acoustic signal based on the analog signal; and a
smart card interface unit sized to accept a smart card programmed
to store a plurality of data associated with a user.
86. The subscriber unit of claim 85, wherein the user interface
unit further comprises a processor in communication with a
memory.
87. The subscriber unit of claim 86, wherein the memory comprises a
program logic executable by the processor, the program logic
comprising instructions for causing the processor to manipulate
caller identification information related to an incoming call.
88. The subscriber unit of claim 86, wherein the memory comprises a
program logic executable by the processor, the program logic
comprising instructions for causing the processor to provide caller
identification information related to an incoming call to a display
in communication with the processor.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present invention is related to the following co-pending
patent applications that are assigned to the same assignee as the
present invention, the subject matter of which are incorporated
herein by reference thereto: [0002] 1. "Method and Apparatus for
Providing a Derived Digital Telephone Voice Channel," Ser. No.
08/742,164, filed on Nov. 1, 1996. [0003] 2. "Home Gateway System
Telephony Functions and Method," Ser. No. 09/061,833, Filed on Apr.
16, 1998.
TECHNICAL FIELD
[0004] The present invention relates to telecommunication systems,
and in particular to subscriber units and methods for interfacing
with digital lines.
BACKGROUND OF THE INVENTION
[0005] Most telephone service subscribers today use familiar analog
Plain Old Telephone Service ("POTS") for placing ordinary voice
telephone calls. POTS is typically delivered over a subscriber loop
of copper wires installed between each subscriber location, such as
a home or office, and the local telephone company ("telco") central
office. Over the pair of copper wires, voice signals are
transmitted between subscribers and the telco central office. The
central office then provides circuit-switching equipment to
establish connections between subscribers. In such a
circuit-switched system, a circuit connection is established for
each call and is maintained for the duration of the call.
[0006] Recently, on-line computer services, such as the Internet,
have changed the way subscribers use their telephones. On-line
computer services typically make a dial-up telephone number
available for users with a modem to access the service. Many users
of on-line computer services now spend several hours each day on
the telephone connected to services such as the Internet. Such a
usage pattern ties up the telephone for incoming calls and causes a
strain for other members of the household who wish to place calls.
In response, households have added a second telephone line for
computer data traffic. To provide a second telephone line, a second
pair of copper wires is usually provided between the subscriber's
location and the telco central office. In addition to more copper
wiring, a second telephone line also requires additional central
office connection and transmission equipment.
[0007] Recently, higher capacity data transmission services have
become available to carry a subscriber's computer data to remote
computer systems. Such data transmission services often carry data
on the same copper pair utilized by POTS. To allow simultaneous
data and POTS service and provide greater bandwidth, higher
capacity data services operate at frequencies above the 1 KHz to 4
KHz voice frequency band used by POTS. For example, such data
services may operate in the frequency range around 80 KHz or
higher.
[0008] The growing popularity of on-line computer services has also
challenged the assumptions upon which the telephone network was
constructed. The public switched telephone network (PSTN) is
designed with the assumption that only about 10% of residential
users and 20% of business users are using the telephone at any
given time. The PSTN telephone line and associated
circuit-switching equipment are thus designed to be shared by only
the fraction of subscribers actually using the telephone at any
time. Now, many households use the telephone for several hours each
day to carry data traffic to computer services. Using a POTS
circuit-switched telephone call to carry data traffic inefficiently
consumes hardware resources, since a dedicated circuit connection
is consumed for the entire duration of the call.
[0009] More recently, packet-switched data networks have been
established to carry high-speed data traffic between distributed
computer systems. In addition to providing higher data rates,
packet-switched networks are more hardware efficient than
circuit-switched networks for carrying data. A packet-switched
network establishes a virtual circuit connection which uses
transmission resources only when data is actually transmitted. Such
a virtual connection is well suited for users of computer services
who are connected for long periods of time and spend a relatively
small proportion of time actually transmitting and receiving
data.
[0010] Despite the change in communication needs and usage
patterns, most data traffic from homes or small offices is carried
by POTS voice lines.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The invention is pointed out with particularity in the
appended claims. However, other features of the invention will
become apparent and the invention will be best understood by
referring to the following detailed description in conjunction with
the accompanying drawings in which:
[0012] FIG. 1 shows a schematic diagram of a telephone network in
accordance with the present invention.
[0013] FIG. 2 shows a block diagram of the telco central office 20
of FIG. 1 in accordance with the present invention.
[0014] FIG. 3 shows a schematic diagram of a telephone subscriber
location 10 such as a typical home or small office in accordance
with the present invention.
[0015] FIG. 4 shows a block diagram of a tandem location in
accordance with the present invention.
[0016] FIG. 5 presents a block diagram representation of an example
interworking unit in accordance with the present invention.
[0017] FIG. 6 presents a block diagram of a subscriber unit in
accordance with the present invention.
[0018] FIG. 7 presents a block diagram representation of an user
interface unit in accordance the present invention.
[0019] FIG. 8 presents a perspective view of a subscriber unit in
accordance with the present invention.
[0020] FIG. 9 presents a perspective view of a subscriber interface
unit in accordance with the present invention.
[0021] FIG. 10 presents a block diagram representation of a
converter in accordance with the present invention.
[0022] FIG. 11 presents a block diagram representation of an
interface unit in accordance with the present invention.
[0023] FIG. 12 presents a block diagram representation of an
interface unit in accordance with the present invention.
[0024] FIG. 13 presents a flowchart representation of a method in
accordance with the present invention.
[0025] FIG. 14 presents a flowchart representation of a method in
accordance with the present invention.
[0026] FIG. 15 presents a flowchart representation of a method in
accordance with the present invention.
[0027] FIG. 16 presents a flowchart representation of a method in
accordance with the present invention.
[0028] FIG. 17 presents a flowchart representation of a method in
accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] The various embodiments of the present invention yield
several advantages over the prior art. In several embodiments, the
telecommunication system of the present invention includes a
subscriber unit, and methods for use therewith, for accessing one
or more derived digital telephone lines carried over a digital
subscriber line. Other embodiments of the present invention are
directed toward a subscriber interface unit that provides similar
functionality to a standard analog telephone set.
[0030] FIG. 1 shows a schematic diagram of a telephone network in
accordance with the present invention. Telephone subscribers 10 are
typically serviced by analog telephone lines carried to the central
office 20 by a subscriber loop 12 including twisted pairs of copper
wires. A number of subscribers 14 may also be connected by
subscriber loops to a remote terminal 16 which combines a number of
subscribers 14 onto a digital multiplexed data line 18 for
transmission to the central office 20. For example, a 24 channel
multiplexed T1 line is commonly used in North America for the data
line 18.
[0031] Typically, a number of central offices 20 are connected by
direct trunk circuits 22 or through tandem locations 30. The tandem
locations 30 provide trunk circuits 22 to connect two central
offices or other tandem locations 30. The tandem locations 30 can
thus provide connections between central offices which do not have
direct interconnecting trunks. It is to be understood that
telephone switching networks may have multiple levels of tandem
switching or other network topologies. The unique features of the
present invention will be identified with respect to the features
of the components of the network and their unique
configuration.
[0032] FIG. 2 shows a block diagram of the telco central office 20
of FIG. 1 in accordance with the present invention. The central
office 20 preferably includes a means to provide analog telephone
lines such as conventional POTS. Conventional POTS is typically
handled by the local telephone switching device 23. Local telephone
switching devices such as a Northern Telecom DMS-100 or Lucent No.
5 ESS are well known to those skilled in the art. In alternative
embodiments, an analog telephone line may also be provided by a
Centrex type service or private branch exchange (PBX). As known to
those skilled in the art, an analog telephone service may also be
provided by a digital carrier system such as a T1 carrier or other
type of concentrator.
[0033] In addition to POTS service, the central office may also
include a means to provide a digital data line. For example, a
digital data line may be implemented by a digital subscriber line
access multiplexer (DSLAM) 24 to multiplex traffic from digital
subscriber loops. Digital subscriber loops or digital carrier
systems provided by remote terminal 16 and office terminal 25
provide digital data lines which enable subscribers 10 (FIG. 1) to
transmit large amounts of digital multiplexed data traffic over the
POTS twisted pair telephone line. The digital subscriber loop is
preferably an Asymmetric Digital Subscriber Line (ADSL). ADSL
typically implements a digital subscriber line with a maximum data
rate from the central office 20 to the subscriber 10 which is
higher than the maximum available data rate from the subscriber 10
to the central office 20. For example, ADSL typically provides an
asymmetric data rate of 1.5 megabits-per-second (mbs) to the
subscriber from the central office and about 400
kilobits-per-second (kbs) from the subscriber location to the
central office. Most preferably, ADSL implements an ATM data
transmission protocol between the subscriber 10 (FIG. 1) and the
central office 20. Of course, other types of data transmission
protocols may be utilized. In alternate embodiments, the digital
data line may be provided by other types of digital carrier systems
such as a SONET based digital systems.
[0034] As shown in FIG. 2, the subscriber loop pairs 12 carrying
both analog voice and digital data traffic from subscribers 10 to
the central office 20 are terminated at a main distribution frame
(MDF) 26. From the MDF 26, the subscriber loops 12 are connected to
a means for separating POTS voice 32 frequencies from digital data
traffic 34 such as a splitter 28, for example. Preferably, the
splitter 28 is implemented by the DSLAM 24. The internal operation
of the splitter 28 will be described later in more detail in
connection with a splitter at the subscriber 10.
[0035] The splitter 28 preferably has two outputs: one for POTS
signals and another for data traffic. From the splitter 28, the
separated POTS voice signals 32 are connected back to the MDF 26
and onto the local switching device 23 handling POTS telephone
calls. The data traffic output of the splitter 28 is directed to
the DSLAM 24 to multiplex the digital data into a format suitable
for transport on a data network 40. Preferably, the DSLAM 24
multiplexes and packages a number of lower signal rate digital data
lines to a SONET OC-3 or a DS-1 rate signal which is carried by a
fiber optic network. Depending on the data network 40, the DLSAM 24
may operate at higher bit rates such as those appropriate for SONET
OC-12. It should be understood that the data network 40 may be of
many different topologies. Preferably, the data network 40 is
connected to a tandem location 30 to allow access to other central
offices.
[0036] In the case of subscriber loops that are connected to the
central office through a digital loop carrier system (i.e., a
remote terminal 16 and an office terminal 25), the DSLAM 24 and its
splitter 28 are preferably placed at the remote terminal 16. The
data and voice signals are separated with the splitter 28, as
described above. The voice signals are carried on the digital loop
carrier system to the office terminal 25 where they are connected
through the MDF 26 to the local circuit switch 23. Preferably, the
data signals are carried on a separate optical fiber or SONET frame
in the carrier system so that they can easily be separated from the
voice signals in the office terminal 25. These signals are
transmitted from the office terminal to the data network 40.
[0037] FIG. 3 shows a schematic diagram of a telephone subscriber
location 10 such as a typical home or small office in accordance
with the present invention. A network interface device (NID) 41
connects the subscriber to the public switched telephone network
(PSTN). The subscriber loop 12 between the subscriber 10 and the
central office 20 is terminated at the NID 41. Customer premise
equipment (CPE) such as a standard telephone set 52 or other CPE
equipment such as a key system, PBX, or computer network 56 to
access the PSTN is connected at the NID 41. Voice signals from an
analog telephone line 53 and data signals from a digital data line
55 are typically carried to the subscriber 10 on the same
subscriber pair 12.
[0038] In the preferred embodiment of the invention, the NID 41
includes a means for separating voice frequency signals from data
signals. Preferably, a splitter 44 separates voice frequency
signals from the data traffic sharing the subscriber loop 12 wire
pair. For example, to separate POTS from data traffic, the splitter
44 typically includes a high-pass filter 46 and a low-pass filter
48. To separate POTS voice signals, the low-pass filter 48 blocks
high frequency signals, for example signals above 5 KHZ, passing
only lower voice frequency signals on a conventional CPE POTS loop
50. The voice signals on the CPE POTS loop 50 are connected to
standard telephone 52 such as a Bell 103 set providing conventional
POTS service. It should be noted that a conventional computer modem
54 can also utilize the conventional CPE POTS loop 50.
[0039] To recover data traffic, the high-pass filter 46 blocks low
frequency signals, for example signals below 5 KHz, leaving only
high frequency data traffic signals to be sent out on a separate
CPE data network loop 56. The CPE data network loop 56 is connected
to CPE equipped to access data traffic, for example, a network of
personal computers. In the preferred embodiment, the CPE data
network 56 implements an asynchronous transfer mode network (ATM).
Each of the personal computers 58 is equipped with a ATM network
interface card (NIC) to allow the computer to access the CPE data
network 56. The NIC 41 preferably also includes data segmentation
and reassembly (SAR) capability to packetize data for transmission
on the data network 56. Of course, other types of computer
networks, such as an Ethernet network, may also be implemented.
[0040] Preferably, the CPE data network 56 is also equipped with
one or more digital telephones 60 capable of interfacing the data
network 56 to allow a subscriber to place a voice telephone call
over the CPE data network 56. For example, a digital telephone 60
may be implemented with one of the personal computers 58 on the
data network 56 by adding a telephone handset and an appropriate
NIC with telephony functions. The telephone handset transmits and
receives analog voice signals similar to a conventional handset.
The computer/NIC provides SAR capability for converting analog
voice to a digital packet stream for transmission over the CPE data
network 56. The data network 56 also carries the basic telephony
signaling functions. One such system capable of providing such a
digital telephone is an ATM network based telephone system from
Sphere Communications in Lake Bluff, Ill.
[0041] Using the CPE data network 56, the subscriber 10 can place a
voice call using a telephone line derived from the digital data
line. POTS service operates as a usual over the POTS wiring 50 to
provide regular telephone service such as a telephone line carrying
analog voice signals. In addition, the data network 56 with digital
telephone 60 also has the capability to place voice telephone calls
using one or more derived voice lines implemented through the data
network, as will be explained below in more detail.
[0042] FIG. 4 shows a block diagram of a tandem location in
accordance with the present invention. The Class 5 local switch 70
typically connects local subscriber loops to the telephone network,
while a separate tandem voice switch (not shown) provides
conventional circuit-switched connections for directing POTS
traffic between central offices 20 (FIG. 1) of the PSTN. Class 5
local switches such as the Lucent 5 ESS and the Nortel DMS 100, and
tandem voice switches such as the Lucent 4ESS and the Nortel DMS
250 are known to those skilled in the art. In comparison, the means
for providing data access to data networks is preferably a packet
switch handling digital data traffic. For example, a data access
tandem switch 72 provides access to data networks carrying digital
data traffic. Preferably, the data networks are equipped to accept
ATM packet-switched connections. The data access tandem switch 72
is an ATM fabric switch configured to provide virtual connections
on demand between end users and providers of data networks and
services. The data access tandem switch 72 may connect end users to
various network service providers (NSPs) such as UUNet, MCI,
Sprintnet, and AADS.
[0043] The tandem location 30 may also include a means to interface
the data access tandem 72 and the Class 5 switch. For example, an
interworking unit (IWU) 74 may implement an interface between the
data access tandem switch 72 and the Class 5 switch 70 of the PSTN.
The IWU 74 enables voice telephone calls carried by the data
network 40 to access the PSTN through the Class 5 switch 70. The
IWU 74 is capable of converting a voice telephone call in the data
network protocol from the data access tandem switch 72 into the
circuit-switch protocol of the Class 5 switch 70. Preferably, the
IWU 74 interfaces an ATM packet data stream to a multiplexed
circuit-switch protocol with dynamic allocation of voice channels
such as TR-303.
[0044] FIG. 5 presents a block diagram representation of an example
interworking unit in accordance with the present invention. In
particular, the IWU 74 performs the SAR 76 of voice data from an
ATM stream into a analog voice signal. The analog voice signal is
then converted 78 into the data protocol such as a TR-303 protocol.
More preferably, as seen in FIG. 4, the IWU 74 converts the
packetized ATM voice streams to a digital PCM format which is then
converted to the desired TR-303 protocol. It should be noted that
the local switch 70 may also be directly connected to a data access
tandem 72 without the IWU interface 74. Newer generation digital
switches may be capable of directly interfacing with the data
transfer protocol of the data access tandem 72. For example, new
generation circuit-switches may directly accept an ATM data stream
for switching into the PSTN without the need for an IWU.
[0045] While a TR-303 protocol is described above, other protocols
may likewise be used in accordance with the present invention. In
particular, other protocols including a PRI protocol, TR-08
protocol or a TR-57 protocol could likewise be used within the
scope of the present invention.
[0046] With the system of FIGS. 1-5, a derived voice telephone line
using the data network can be implemented and utilized in
conjunction with the methods and systems that follow.
[0047] A caller places a digital voice call similar to an ordinary
telephone call using the digital telephone 60 of FIG. 3. The SAR
function of the digital telephone 60 converts the caller's analog
voice signals to a packetized digital data stream for transport
over the subscriber data network 56. Preferably, the packetized
data stream is in an ATM format.
[0048] The subscriber data network 56 carries the derived telephone
line data stream to the subscriber loop 12 where it is transported
on a digital data line to the central office 20 along with POTS
traffic. Note, the derived telephone line uses the digital data
line of the subscriber data network 56, leaving the POTS telephone
line available for analog telephone voice calls.
[0049] At the central office 20 shown in FIG. 2, the splitter 28
separates the derived telephone line data stream from POTS traffic.
The derived telephone line data stream is multiplexed by the DSLAM
24 together with a number of data streams or derived telephone line
data streams from other subscribers. For example, the DSLAM 24 may
combine data streams from a number of different subscribers into a
higher rate digital signal such as a DS-3 or OC-3 signal. The
telephone line data stream is then carried by the OC-3 signal over
the data network 40 to the tandem location 30.
[0050] At the tandem location 30 shown in FIG. 4, the derived
telephone line and data sessions are switched by the data access
tandem 72. Preferably, data sessions to a NSP are directly switched
by the data access tandem 72 to the desired NSP without entering
the PSTN. For voice calls which must enter the PSTN, the data
access tandem 72 directs the derived telephone line data streams to
the IWU 74.
[0051] The IWU 74 preferably converts the derived telephone line
data stream to a voice signal in a TR-303 format which can be
switched by the Class 5 telephone switch 70. Through the Class 5
switch 70, the derived voice call enters the PSTN and is switched
as a POTS call. If needed, a separate tandem switch establishes a
circuit connection to the desired central office 20.
[0052] FIG. 6 presents a block diagram of a subscriber unit in
accordance with the present invention. In particular, a subscriber
unit 100 allows connection with a public switched telephone
network. The public switched telephone network has at least one
switch and at least one digital subscriber line 102, such as
described in FIGS. 1-5, in communication with the switch. In
accordance with the present invention, the subscriber unit 100 is
operable to send and receive voice calls over the public switched
telephone network.
[0053] While the various embodiments of the present invention have
been described in conjunction with a public switched telephone
network, these embodiments could similarly apply to voice
communications over other communication networks. In particular,
telephone calls, within the scope of the present invention, can be
transmitted using a data communications network such as the
Internet as a transport medium for a least a portion of a call. In
these embodiments of the present invention the functionality of an
analog local switch or digital switch could be performed by a
server and router corresponding to a local Internet service
provider or could include an IP gateway in combination with a
central office switch. Further the switch of the present invention
could be a central office circuit switch or a packet switch
depending on the nature of the network.
[0054] The subscriber unit 100 includes a digital subscriber line
interface unit 104 receives the plurality of data packets from the
digital subscriber line 102 and identifies selected ones of the
plurality of received data packets corresponding to a received data
stream of a first derived digital telephone. The subscriber unit
100 is further operable to transmit, on the digital subscriber
line, a plurality of transmitted data packets corresponding to a
transmitted data stream of the first derived digital telephone
line.
[0055] In one embodiment of the present invention data packets are
formatted in accordance with the Asynchronous Transfer Mode (ATM)
protocol. Further, a hierarchical protocol structure could likewise
be used encompassing, for instance, an Ethernet protocol carried by
ATM or an internet protocol (IP) such as TCP/IP carried by ATM.
However, other packet data protocols and hierarchical structures
and combinations could likewise be implemented within the scope of
the present invention.
[0056] Packets received by the subscriber unit 100, destined for
receipt by subscriber unit 100 include an address, consistent with
the particular protocol or protocols used for formatting the data
packets, that corresponds to either the subscriber unit 100 or to a
corresponding subscriber. In accordance with an embodiment of the
present invention whereby an IP is used, data packets directed to
the subscriber unit 100 could be identified based on a particular
IP node address or URL corresponding to either the particular
subscriber unit 100 or to a particular subscriber using subscriber
unit 100. Alternatively, an ATM address could be used for the same
purpose in an ATM protocol environment.
[0057] The subscriber unit 100 further includes a coder/decoder
106. The coder/decoder 106 receives the transmitted data stream
from analog-to-digital (A/D) converter 108 and codes the
transmitted data stream into the plurality of transmitted data
packets. The coder/decoder 106 also receives the plurality of
received data packets from the digital subscriber line interface
unit 104 and decodes the plurality of received data packets into a
received data stream to be transmitted to the digital-to-analog
(D/A) converter 110 on line 122.
[0058] Analog-to-digital converter 108 converts a transmitted
analog signal from user interface unit 112 into the transmitted
data stream. Digital-to-analog converter 110 converts the received
data stream into a received analog signal for transmission to the
user interface unit 112 on line 124.
[0059] In this fashion, digital subscriber line interface unit 104,
coder/decoder 106, A/D converter 108 and D/A converter 110 operate
in concert to send and receive basic telephony signaling between
the digital subscriber line 102 and an user interface unit 112.
This user interface unit 112 provides the basic functionality of a
standard analog telephone-set. In particular, the user interface
unit 112 provides an interface to a user of the subscriber unit
and, at a minimum, generates the transmitted analog signal sent to
A/D converter 108 and generates an acoustic signal based on at
least a portion of the received analog signal.
[0060] In an alternative embodiment of the present invention, a
direct data path 114 is provided for communicating with the user
interface unit 112. This data path could carry the transmitted data
stream, the received data stream or both. In embodiments of the
present invention where the user interface unit 112 includes a
processor, data path 114 is advantageous to allow direct digital
communication without need for the conversion to analog and then
back to digital data.
[0061] FIG. 7 presents a block diagram representation of an user
interface unit in accordance with the present invention. In
particular, user interface 112 of FIG. 6 is shown in more detail in
accordance with various alternative embodiments.
[0062] User interface unit 112 optionally includes a telephone
tip/ring converter 125 that converts the analog signal line 122
from the D/A converter 110 to appear as a typical tip/ring pair 127
to telephone line interface unit 120. In particular, tip/ring
converter 125 adds a voltage bias and provides any necessary
generation or conversion of signal levels from line 122 to appear
as a standard analog telephone line, even though the analog signals
such as voice and ringing signals on line 122 where transported
over a packet data line. In various embodiments of the present
invention, the functionality of D/A converter 108, A/D converter
110 and tip/ring converter 125 perform the functions of a line card
used in conjunction with a digital central office switch.
[0063] Optional telephone line interface unit 120 provides an
interface between processor 126 and tip/ring converter 125 by
converting basic telephony signals such as on-hook, off-hook, and
ring signals for detection by the processor or for generation by
the processor to the tip/ring pair 127. In this embodiment, keypad
134 and DTMF tone generator 128, switch hook 132, alert signal
generator 130 and telephone handset 140 are further coupled to the
tip/ring pair 127 for directly responding to, and/or for
generating, the basic telephony signals carried by tip/ring pair
127 in a manner familiar to those skilled in the art.
[0064] While the present invention is described as including a
switch hook, other similar devices could likewise be used,
including a flash key or a receive button, within the scope of the
present invention.
[0065] However, processor 126, including a plurality of interface
ports (not specifically shown) and general memory 144, is likewise
capable of responding to and/or directly generating the basic
telephony signals in a similar manner. In this fashion, dialed
numbers can be recorded and stored for redialing or speed dialing
purposes, conditions requiring distinctive ringing patterns can be
detected and distinctive rings can be generated, stored voice
signals can be generated and received voice signals can be
analyzed, and on-hook and off-hook signaling can be generated
without the use of the switch hook.
[0066] In an alternative embodiment of the present invention the
functionality supplied by tip/ring converter 125 and telephone
interface unit 120 could be supplemented or supplanted by direct
digital connection 114 to processor 126. The plurality of interface
ports (not specifically shown) of processor 126 could provide the
appropriate conversion from the analog devices such as keypad 134
and DTMF tone generator 128, switch hook 132, alert signal
generator 130 and telephone handset 140.
[0067] In various embodiments of the present invention the user
interface unit advantageously includes a display unit. In various
embodiments, this display unit is a liquid crystal display (LCD)
capable of displaying information relating to incoming and outgoing
calls in additional to command and control information for the
operation of the subscriber unit. In particular, a graphical user
interface (GUI) for operation of the telephone is implemented using
the processor 126, the display device 136 and additional keys
138.
[0068] In a further embodiment of the present invention the
additional are distributed adjacent to the display unit, the
plurality of keys operable by the user to activate selected ones of
a plurality of call control options displayed on the display device
adjacent thereto. In this fashion, a plurality of call control
options such as call transfer, hold, redial, conferencing,
forwarding, speed dialing, hands free, line release, line
selection, etc., can be implemented by a user by the presentation
of a menu of commands and by pressing the key adjacent to the
displayed command on the display device.
[0069] The display device 136 is further capable of displaying a
plurality of data relating to an outgoing call, for instance, by
monitoring the digits dialed by the user and by displaying
destination telephone number reflected by these digits. The
processor further is operable to time the duration of the call from
the time the telephone line is off-hook and displaying the duration
on the display device. 14. Call memory 142 is available for storing
the plurality of data relating to an outgoing call for a plurality
of outgoing calls. This data can be retrieved and reviewed by the
user or can be downloaded to an external device coupled to the
subscriber unit through data interface unit 152.
[0070] Processor 126 is further capable of receiving and decoding
caller identification data relating to the identity of an incoming
caller and the display unit is capable of displaying a plurality of
data relating an incoming call. In this fashion, caller ID signals
received during the silent interval between the first and second
rings of an incoming telephone call can be decoded and displayed to
the user before the corresponding line is taken off-hook.
[0071] Similarly, for a subscriber to a caller ID/call waiting
service who is engaged in a conversation with a first caller, the
processor 126 can receive the caller ID information corresponding
to a second caller and display it to a user for determination if
the first caller should placed on hold and the second call should
be answered. Additionally, the call disposition features
corresponding a caller ID/call waiting deluxe could likewise be
implemented using the display and either the keys of keypad 134 or
the additional keys 138.
[0072] Call memory 142 is likewise available for storing a
plurality of data relating to an incoming call for a plurality of
incoming calls. The plurality of data relating the incoming call
includes caller ID information of the calling party, the duration
of the call (if the call was completed), and data indicating if the
incoming call includes a facsimile message. In this embodiment of
the present invention the stored data can be retrieved and
displayed or downloaded as discussed earlier in conjunction with
outgoing call data.
[0073] While many of the forgoing discussions have addressed the
accessing of a single line, in various embodiments of the present
invention the subscriber unit 100 is capable of monitoring and
accessing multiple telephone lines, at least one of which is a
derived digital telephone line. In these embodiments the display
device 136 is capable of showing the status a plurality of lines,
and the user is capable of accessing and placing calls on any one
of a plurality of lines.
[0074] Further, the subscriber unit 100, through the use of
processor 126 and in response to a signal generated by the user
interface unit 112 and in response to an action of the user, is
capable of initiating a connection to a remote central office on
one or more derived digital telephone lines carried by the digital
subscriber line. In this embodiment of the present invention the
processor 126, coupled to the coder/decoder 106, digital subscriber
line interface 104 and coder/decoder 106, is capable of accepting
data corresponding to a second derived digital telephone line in
addition to a first derived digital telephone line, and the
processor 126 is further capable of monitoring the status of the
second derived digital telephone line. More generally, the
subscriber unit 100, in response to a signal generated by the user
interface unit 112 in response to an action of the user, is capable
of initiating up to N additional derived digital telephone lines,
where N is greater than 2.
[0075] In an additional embodiment of the present invention the
user interface unit 112 further comprises a smart card interface
unit 146 capable of accepting and communicating with a smart card
(not specifically shown). Preferably, smart card interface unit 146
is compatible with PCMCIA standards and can accept any of a wide
variety of such smart cards. In one such embodiment, the smart card
inserted into the smart card interface unit 146 stores a plurality
of data associated with the user and wherein the processor 126 is
capable of downloading a plurality of smart card data from a smart
card so that the use of the subscriber unit 100 can be personalized
to the particular user.
[0076] In one embodiment of the present invention the plurality of
smart card data includes a protocol address such as a IP node
address or an ATM address corresponding to the user. In this
fashion, the address of the telephone could change or be overridden
by the address of the user downloaded from the smart card so that
calls directed to the user could be sent to the particular
subscriber unit 100 over a derived digital telephone line. Once the
data was downloaded from the smart card, the subscriber unit can
automatically register the presence of the subscriber at the
location of the particular subscriber unit 100 by sending a data
message to the remote central office over the digital subscriber
line. Alternatively, the registration of the presence of the user
at the particular subscriber unit 100 containing the smart card
could be optionally effectuated only upon activation of the user
either in response to a query by the subscriber unit, such as in
response to a message displayed on the display device 136 or by
action of the user in the absence of such a query.
[0077] In a further embodiment of the present invention the smart
card data contains other personal options of the user including
custom set-up and command options for the subscriber unit. These
set-up and command options could include device macros for
performing a series of commands on the subscriber unit at the touch
of a single button and could also include a user's speed dial
list.
[0078] In another embodiment of the present invention the user
interface unit 112 further includes a keyboard 150 and wherein the
subscriber unit is capable of communication with a first data
service over the digital subscriber loop. In this fashion the
subscriber unit 100 can operate as a PC or network computer to
access data services such as internet or world wide web services
from the subscriber unit 100. In one such embodiment the
communication with the first data service over the digital
subscriber loop could use data packets that do not correspond to a
derived digital telephone line. However, one or more derived
digital lines could, nevertheless, be used for this purpose. In
this embodiment the user interface unit 112 further includes a
display driver 148 for driving a remote display device. In an
applications where communicating with a first data service the
device driver 148 allows the use of a larger display than might be
integrated in the subscriber unit itself.
[0079] In a further embodiment of the present invention, the
subscriber unit 100 specifically includes the functionality of a
fax modem. In the fashion, the subscriber unit 100 is operable to
send a receive a plurality of fax messages. In this embodiment a
received fax message or fax message to be sent could be
communicated to/from the subscriber unit using the data interface
unit 152 in combination with a document scanner or a printer or
other specific device.
[0080] In an additional embodiment of the present invention, the
subscriber unit, under the control of processor 126, performs the
functionality of a answering machine where greetings are stored and
played to incoming callers, and messages from callers are stored in
a memory device such as general memory 144.
[0081] FIG.8 presents a perspective view of a subscriber unit in
accordance with the present invention. In particular, a subscriber
unit 100 is presented that incorporates the various features and
options presented in conjunction with the descriptions of FIG. 6
and FIG. 7. Housing 160 includes an integral display device 136,
keypad 134 and telephone handset 140. Additional keys 138 (that are
not adjacent to the display device 136) and additional keys 138'
that are adjacent to the display device 136 provide access to
advanced controls and features of the subscriber unit 100. Smart
card slot 162 corresponds to smart card interface unit 146 disposed
within the housing. Display device jack 166 is coupled to display
driver 148 within the housing 160 and data interface jack 164 is
coupled to data interface unit 152 also disposed within the housing
160.
[0082] FIG. 9 presents a perspective view of a subscriber interface
unit in accordance with the present invention. In particular, FIG.
9 presents a subscriber interface unit for use in a
telecommunication system including a switch, a local loop coupling
the switch to a subscriber location. In this embodiment, a segment
of the local loop includes copper twisted pair and the asymmetrical
digital subscriber line is carried by the local loop. Further, the
asymmetrical digital subscriber line carries a plurality of derived
digital telephone lines as described in conjunction with FIGS. 1-5.
The subscriber interface unit of FIG. 9 advantageously couples the
asymmetrical digital subscriber line to an analog land-line
telephone.
[0083] Subscriber interface unit 180 includes a housing 182 having
a top surface 184 and a bottom surface 186 substantially coplanar
to the top surface. An electrical coupler 188 provides a connection
to a cable capable of carrying the asymmetrical digital subscriber
line. An RJ-11 jack 190 provides a connection to a cable of the
analog telephone (not specifically shown). A converter 200,
disposed within the housing, coupled to the electrical coupler 188
and to the RJ-11 jack 190, converts the first analog signals
generated by the analog telephone into a first plurality of data
packets for transmission to a selected one of the plurality of
derived digital telephone lines and converts a second plurality of
data packets received from the selected one of the plurality of
derived digital telephone lines into a second analog signal for
transmission to the analog telephone.
[0084] In a particular embodiment of the present invention the
subscriber interface unit 180 includes several optional features
that correspond to features described in conjunction with the
subscriber unit 100. Components that are common with subscriber
unit 100 are assigned common reference numerals. In addition,
subscriber unit 180 includes a first indented portion 192 of top
surface 184 for accepting the analog telephone on top thereof. A
plurality of non-skid feet are coupled to the bottom surface 186 of
the housing 182.
[0085] While an RJ-11 jack 190 is shown for coupling to the analog
land-line telephone, many other electrical connections including
other plug and jack combinations are possible within the scope of
this embodiment of the present invention. In a one embodiment of
the present invention the digital subscriber line is carried by the
standard telephone wiring within a home. In this embodiment,
electrical coupler 188 is also implemented using an RJ-11 jack,
however, like the RJ-11 jack 190, other electrical connection
options are possible within the broad scope of the present
invention.
[0086] FIG. 10 presents a block diagram representation of a
converter in accordance with the present invention. In particular,
a converter 200 is presented for use with the subscriber interface
unit 180 of FIG. 9. Digital subscriber line 102 is attached to
electrical coupler 188. An analog land-line telephone is coupled to
the converter via line 204 connected to RJ-11 jack 190. Components
that are common with subscriber unit 100 are assigned common
reference numerals. Converter 200 operates in a manner similar to
subscriber unit 100, however, some of the components of subscriber
unit 100 are supplied by an analog land-line telephone that is
attached to the unit. In other words, the functionality of user
interface unit 112 is supplied by interface unit 202 in combination
with the analog land-line telephone. For the purposes of this
disclosure the term "subscriber unit" should include the various
embodiments of subscriber unit 100 as well as the various
embodiments of subscriber interface unit 180 in combination with an
analog land-line telephone.
[0087] In accordance with the present invention a multi-line analog
telephone can be coupled to the subscriber interface unit 180. In a
manner similar to subscriber unit 100, the combination of
subscriber interface unit 180 and the multi-line analog land-line
telephone is capable of accessing and monitoring the plurality of
telephone lines and is further capable of selecting one of the
plurality of telephone lines for conducting a voice call. The
converter 200 further is capable of converting a third plurality of
data packets received from an additional one of the plurality of
derived digital telephone lines into a third analog signal for
transmission to the analog telephone.
[0088] FIG. 11 presents a block diagram representation of an
interface unit in accordance with the present invention. In
particular, user interface unit 202 is shown for use in accordance
with one embodiment of the converter 200 of FIG. 10. Lines 122 and
124 from the A/D converter 108 and D/A converter 110 are coupled to
tip/ring converter 125 as described in conjunction with several
embodiments of subscriber unit 100. The output 204 appears as a
standard tip and ring pair to the analog land-line telephone.
[0089] The user interface unit 202 of FIG. 11 presents minimal
functionality. The inclusion of additional functions for subscriber
interface unit 180 can be desirable. In particular, many of the
additional functions described in conjunction with subscriber unit
100 can likewise be included in subscriber interface unit 202 in
accordance with the present invention. While the subscriber
interface unit 180 of FIG. 9 does not present each of these
additional functions, these functions may, nevertheless be included
as described in conjunction with an alternative embodiment for
interface unit 202 presented in FIG. 12.
[0090] FIG. 12 presents a block diagram representation of an
interface unit in accordance with the present invention. In
particular, an alternative embodiment of interface 202 designated
by reference numeral 202' is presented. In this embodiment,
numerous features of subscriber unit 100 are included. Components
that are common with subscriber unit 100 are assigned common
reference numerals. The output 204 of tip/ring converter 125 is
coupled to the analog land-line telephone as well as to telephone
line interface unit 120. Processor 126, display device 136,
additional keys 138, call memory 142, general memory 144, smart
card interface unit 146, display driver 148, keyboard 150 and data
interface unit 152 function as previously described in conjunction
with user interface unit 112.
[0091] FIG. 13 presents a flowchart representation of a method in
accordance with the present invention. In particular, a method for
initiating a call is presented for use with various embodiments of
the subscriber unit 100 or the various embodiments of subscriber
interface unit 180 in combination with an analog land-line
telephone.
[0092] The method begins in step 300 receiving an off-hook signal,
generated by the subscriber unit in response to an action of a
user. In one embodiment of the present invention this signal would
be generated by the switch hook of a subscriber unit responding to
the handset going off-hook. In other embodiments, an off-hook
signal could be generated by the user selecting an additional key
of the subscriber unit such as a "handsfree" key used to initiate a
call using a speakerphone function of the subscriber unit or a
"send" key commonly used by cellular telephones to initiate a
call.
[0093] The method continues in step 302 by initiating a first
derived digital telephone line of the plurality of derived digital
telephone lines in response to the off-hook signal. In particular,
the off-hook signal is converted to data in a transmitted data
stream that is converted to a transmitted data packet that is
transmitted along the digital subscriber line to a switch through
an interworking unit. This begins a data packet exchange between
the switch and the subscriber unit carrying the basic telephony
signals corresponding to the derived digital telephone line. In one
embodiment of the present invention the data packet is addressed to
an interworking unit where it is converted to a signaling protocol
for interface to the switch.
[0094] FIG. 14 presents a flowchart representation of a method in
accordance with the present invention. In particular, a method for
initiating and terminating a call is presented for use with various
embodiments of the subscriber unit 100 or the various embodiments
of subscriber interface unit 180 in combination with an analog
land-line telephone.
[0095] Steps 300 and 302 proceed as described in conjunction with
the method described in FIG. 12. The method continues in step 304
by generating a line-in-use signal, at the subscriber unit,
indicating a first derived digital telephone line is in use. In
step 306, a visual indicator is generated at the subscriber unit in
response to the line-in-use signal. In a preferred embodiment of
the present invention, the visual indicator includes a display, on
display device 136, of the destination telephone number and of the
duration of the call. Optionally, the visual display includes an
indicator of an assigned number for the derived digital line. Thus,
in a multi-line environment, a visual designator such as "line 1"
can be displayed as well.
[0096] The method continues in step 308 by monitoring, at the
subscriber unit, the content of at least one of the plurality of
data packets of the digital subscriber line. In a preferred
embodiment of the present invention, each of the incoming packets
is continuously monitored by the subscriber unit to determine if
any of the plurality of incoming data packets has an address
corresponding to the subscriber unit. If so, the data payload from
each such packet is transformed to the received data stream for
transfer to the user interface unit to conduct the call. Further
the transmitted data stream would be converted into a plurality of
data packets addressed to the switch.
[0097] In step 310, an on-hook signal is received, generated by the
subscriber unit in response to an action of a user. In one
embodiment of the present invention this signal would be generated
by the switch hook of a subscriber unit responding to the handset
being placed on-hook. In other embodiments, an on-hook signal could
be generated by the user selecting an additional key of the
subscriber unit such as a "line release" key used to terminate a
call using a speakerphone function of the subscriber unit.
[0098] In step 312 the derived digital telephone line is terminated
in response to the on-hook signal. In particular, the call is
terminated when the on-hook signal is transmitted to the switch and
the subscriber unit stops creating a transmitted data stream and
transmitted data packets. The exchange of data packets between the
switch and the subscriber unit corresponding to the derived digital
telephone line ends. In step 314, the visual display indicating the
line is use is also terminated with the termination of the
call.
[0099] FIG. 15 presents a flowchart representation of a method in
accordance with the present invention. In particular, a method for
responding to an incoming call is presented for use with various
embodiments of the subscriber unit 100 or the various embodiments
of subscriber interface unit 180 in combination with an analog
land-line telephone. One of ordinary skill in the art will
recognize, based on the disclosure herein, that this method may be
used in conjunction with the other methods of the present invention
described herein.
[0100] The method begins is step 320 by monitoring the content of
at least one data packet to detect an incoming call. As previously
discussed, in a preferred embodiment of the present invention the
step of monitoring is performed continuously. Prior to the
initiation of an outgoing call or the receipt of an incoming call,
the step of monitoring is important to both the detection of usage
of other derived digital lines and the detection of an incoming
call for the particular subscriber unit. During a call the step of
monitoring is important to identifying data packets that correspond
to the call in progress.
[0101] The method continues in step 322 by determining if a
received packet indicates an incoming call. After receiving a data
packet addressed to the particular subscriber unit, the data
portion of the packet is translated to a received data stream--the
data indicating a ring signal from the central office. In response,
the method initiates ringing as shown in step 324. In step 326,
caller ID information, that is, in a preferred embodiment,
transmitted between the silent interval between the first and
second ringing signals, is decoded, displayed on the display
device, and is stored in a call memory.
[0102] The method proceeds in step 328 to determine if an off-hook
signal is received. If an off-hook signal is received, the call is
conducted in step 330 by continuously sending and receiving data
packets corresponding to a derived digital telephone line between
the subscriber unit and the central office for the duration of the
call. In step 332, a line-in-use signal is generated in response to
the off-hook signal and in step 334 a visual indicator is generated
and displayed to the user. In a preferred embodiment of the present
invention this visual indicator includes the duration of the call
and the received caller ID data. The visual indicator may
optionally include a line designator indicating the line number of
the line in use.
[0103] In step 336 the method proceeds by determining if an on-hook
signal is generated in response to an action of the user. In step
338, in response to the detection of an on-hook signal the derived
digital line is terminated. The method continues by returning to
step 320 and continuing to monitor the content of the incoming data
packets for the initiation of an incoming call.
[0104] In a further embodiment of the present invention, when the
remote party engaged in a telephone call on a derived digital
telephone line goes on-hook, the subscriber unit generates an
on-hook signal a predetermined time later to terminate the line in
cases where the remote party has hung-up.
[0105] FIG. 16 presents a flowchart representation of a method in
accordance with the present invention. In particular, a method for
indicating the use of a derived digital telephone line by another
subscriber unit is presented for use with various embodiments of
the subscriber unit 100 or the various embodiments of subscriber
interface unit 180 in combination with an analog land-line
telephone. One of ordinary skill in the art will recognize, based
on the disclosure herein, that this method may be used in
conjunction with the other methods of the present invention
described herein.
[0106] The method begins in step 340 by monitoring, at the
subscriber unit, the content of at least one of the plurality of
data packets corresponding to the digital subscriber line. The
method continues in step 342 by determining that a first derived
digital telephone line is in use based on the content of the at
least one of the plurality of data packets.
[0107] In this embodiment of the present invention, the subscriber
unit monitors the traffic of data packets to determine the presence
of incoming and outgoing calls by other subscriber units that share
the same digital subscriber line. In one such embodiment the
addresses of the other subscriber units is recorded in the
particular subscriber unit of interest so that packets addressed to
the other subscriber units can be read. In an alternative
embodiment of the present invention all incoming data packets are
monitored for the presence of basic telephony signals to determine
if other derived digital telephone lines are in use.
[0108] In step 344 a line-in-use signal is generated, at the
subscriber unit, indicating a first derived digital telephone line
is in use. This line-in-use signal can be used in the subscriber
unit to display information on the status of one or more additional
lines that are use by other subscriber units connected to the same
digital subscriber line.
[0109] In operation, the present invention allows a plurality of
subscriber units to be advantageously connected to a single
subscriber line. The nature of the derived digital telephone line
allows additional telephone lines to be added on demand up to the
bandwidth limits of the digital subscriber loop. All of these lines
can be monitored and accessed by a single subscriber unit connected
to the digital subscriber line. The subscriber unit of the present
invention is capable of performing the advanced features of a
multi-line centrex-based system without the necessity of the
additional hardware. For instance, each subscriber unit can perform
three-way calling, call transfer, call forwarding, call holding
etc.
[0110] FIG. 17 presents a flowchart representation of a method in
accordance with the present invention. In particular, a more
detailed method for indicating the use of a derived digital
telephone line by another subscriber unit is presented for use with
various embodiments of the subscriber unit 100 or the various
embodiments of subscriber interface unit 180 in combination with an
analog land-line telephone. One of ordinary skill in the art will
recognize, based on the disclosure herein, that this method may be
used in conjunction with the other methods of the present invention
described herein.
[0111] Steps 340, 342 and 344 correspond to similar steps presented
in conjunction with FIG. 16. Step 346 proceeds by generating a
visual indicator in response to the line-in-use signal. In a
preferred embodiment of the present invention this visual indicator
includes the duration of the call, the received caller ID data. The
visual indicator further includes a line designator indicating the
line number of the line in use.
[0112] In step 348 an add-a-line signal is received, generated in
response to an action by the user. In one embodiment of the present
invention, this signal is generated by an off-hook signal where a
line is currently in use. In this fashion the subscriber unit
defaults to adding a new line rather than adding the user to a call
on an existing line when the receiver is picked-up during a period
when another derived digital telephone line is in use. In this
embodiment, an existing call would be accessed by a user by
pressing another key, such as a soft key, adjacent to the portion
of display indicating that an call is progress. In an alternative
embodiment the functions could be reversed and an off-hook signal
would default to joining an existing call and an additional key
could be used to generate an add-a-line signal.
[0113] The method proceeds in step 350 by initiating a second
derived digital line by setting up two-way packet data
communication with the local central office. Optional steps 352 and
354 correspond to receiving a hold signal generated by the action
of the user, such a pressing a hold button, and placing the second
derived digital line on "hold". Optional steps 356 and 358
correspond to receiving a signal based on the action of a user
indicating one of a plurality of derived digital lines that are
currently active and accessing the corresponding one of the
plurality of derived digital lines.
[0114] In step 360 an on-hook signal is received and in step 362,
the second derived digital line is terminated in response to the
on-hook signal. These steps are similar in scope to steps described
in conjunction with the methods of FIGS. 14 and 15.
[0115] While various embodiments of the present invention have been
described as having a single address or single telephone number
that corresponds to a subscriber unit. The subscriber unit of the
present invention could likewise respond to a plurality of derived
digital lines corresponding to multiple IP node addresses, URLs,
ATM addresses or telephone numbers. In this fashion, multiple
derived digital lines may be directed to a single subscriber unit
via multiple addresses or multiple telephone numbers.
[0116] The various methods described herein, in a preferred
embodiment, are intended for operation as software programs running
on a computer processor. One of ordinary skill in the art will
recognize that other hardware implementations such as application
specific integrated circuits, programmable logic arrays and other
hardware devices could likewise be constructed to implement the
methods described herein. In should also be noted that the various
methods of the present invention could be stored on a tangible
storage medium such as a magnetic or optical disk, read-only memory
or random access memory and be produced as an article of
manufacture.
[0117] Thus, there has been described herein a concept, as well as
several embodiments including a preferred embodiment, of a
telecommunication system, method and subscriber unit for use
therewith. The various embodiments of methods and systems, by
enabling telecommunications services over a derived digital
telephone line of a digital subscriber line, provide a significant
improvement over the prior art. Additionally, the various
embodiments of the present invention herein-described have other
features that distinguish the present invention from the prior
art.
[0118] It will be apparent to those skilled in the art that the
disclosed invention may be modified in numerous ways and may assume
many embodiments other than the preferred forms specifically set
out and described above. Accordingly, it is intended by the
appended claims to cover all modifications of the invention which
fall the true spirit and scope of the invention.
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